Method for developing photographic elements

ABSTRACT

There is disclosed a method for developing a photographic element which comprises developing a photographic element having photographic layers in a developer containing a water-soluble fluorescent whitening agent, wherein at least one of said photographic layers contains a particular water-soluble polymer or copolymer. In addition, the instant invention also extends to the photographic printing element employed in the method recited above.

United States Patent [191 Tsuji et al.

Filed: Feb. 25, 1971 Appl. No.: 118,990

Related US. Application Data Division of Ser. No. 838,8]2, July 3, 1969, Pat. No. 3,666,470.

Foreign Application Priority Data July I968 u.s. Cl 96/63, 96/82, 96/1 l4 Int. Cl G03c 1/92, 603C 5/26 Dec. 18, 1973 [58] Field of Search 96/114, 82, 63

[56] References Cited UNITED STATES PATENTS 3,628,957 l2/l97l Franco et a] 96/114 Primary Examiner-Ronald H. Smith Att0rneySughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT There is disclosed a method for developing a photographic element which comprises developing a photographic element having photographic layers in a developer containing a Water-soluble fluorescent whitening agent, wherein at least one of said photographic layers contains a particular water-soluble polymer or copolymer. In addition, the instant invention also extends to the photographic printing element employed in the method recited above.

11 Claims, 1 Drawing Figure PATENIEUHEEWISYS 3.779.766

RELATIVE iNTENSITY OF FLUORESCENCE 893% '5? o 8 5 WATER WASHING TIME METHOD FOR DEVELOPING PHOTOGRAPHIC ELEMENTS CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional application of our earlier co-pending application Ser. No. 838,812 filed on July 3, I969, now U.S. Pat. No. 3,666,470 and claims priority from July 4, 1968, based on JapanesePat. application Ser. No. 46708/68.

The present invention relates to a photographic printing element and in particular to aphotographic printing element having improved whiteness in the absence of a matt surface.

Hitherto, in order to improve the whiteness of nonimage (blank) portions of a printed photographic printing element, it has been attempted to incorporate a fluorescent whitening dye, which emits a purple or a blue fluorescence by absorbing ultraviolet rays, in photographic layers, such as a baryta layer, an undercoating, a light-sensitive emulsion layer, a protective layer applied to a support or an image receiving layer of a printing element for diffusion transfer photography (hereinafter, these layers are called photographic layers). Water-soluble polyvinyl pyrrolidone in one of these photographic layers, and water-soluble poly-N-vinyl-S- methyl-2-oxazolidinone have also been incorporated in one of these layers for this purpose.

However, the conventional method of incorporating a fluorescent whitening dye has the drawback that,

more, the greater part of the fluorescent whitening dye present in the photographic layer is removed in the water-washing stage after development, which severely weakens the whitening effect.

The aforesaid method of incorporating water-soluble poly-N-vinyl-S-methyl-2-oxazolidine or water-soluble polyvinyl pyrrolidone in the photographic layer has the drawback that, although the ,whitening effect is higher cornNncoNa --CH CH nrrcomroias i olNa OzNa Therefore, 'an object of the present invention 'is to provide a photographic printing element having improved whiteness by employing a water-soluble fluorescent whitening dye without the accompaniment of the aforesaid drawbacks.

Another object of the present invention is to provide a water-soluble high molecular weight compound to be employed together with a fluorescent whitening dye for improving the whiteness of a photographic printing element by being incorporated in a photographic layer of the element without being accompanied by the aforesaid drawbacks.

We have found that the above objects can be achieved by the incorporation of a fluorescent whitening dye and a watersoluble high molecular weight compound, which compound is-prepared by polymerizing an N-vinylamide compoundrepresented by the formula CH CHNR,COR

wherein R, represents methyl or ethyl and R represents hydrogen, methyl or ethyl, or copolymerizing the above monomer with another comonomer, in at least one of the photographic layers of a photographic printing element, such as, a baryta layer, an undercoating, a light-sensitive emulsion layer, a protective layer, or a diffusion transfer image-receiving layer applied on a support.

The water-soluble fluorescent whitening dye (or fluorescent brightening agent) to be employed in the present invention is one which emits a blue-purple fluorescence (of wave lengths of 430-470 m.u.) by absorbing ultraviolet rays. As fluorescent whitening dyes which may be employed in the present invention, there may be mentioned those known water-soluble fluorescent dyes having a direct dyeing affinity, such as diaminostilbene dyes, benzidine dyes, triazole dyes, imidazole dyes, and imidazolone dyes. Specific examples of such fluorescent whitening dyes are as follows:

Diaminostilbene fluorescent dyes a. Compounds of the formula r N (liken-Grie X l Jl some N N J SOaNa wherein X, Y, X, and Y each represents -NHC H NHC H.,SO Na, OH, NH NHCH CH- SO Na, -OCH CH OH, or --OCH and n represents 5 to 100.

as the degree of polymerization of the polymer to be employed is higher, when a polymer having a high dewherein n represents 5 to I00.

Benzidine fluorescent dyes a. Compounds of the formula wherein R represents H, CH OCH Triazole fluorescent dyes N SOaNa aNa OaNa NaO S Imidazole fluorescent dyes I Compounds of the formula R. I 3 a N wherein R represents H, CH C 1-l -OCH or SO Na and R represents H, CH or CH C- H 011.

lmidazolone fluorescent dye SOzNa The above dye is disclosed in applicants Japanese Patent Application No. 22756/67.

molecular weight compounds having at least one of the repeating units represented by general formulas (9) and (10) Compounds of the formula N SOaM 03M wherein R and R each represents a hydrogen atom, an

' alkyl group having 1-8 carbon atoms, an aryl group having 6-12 carbon atoms, a hydroxyalkyl group having 2-4 carbon atoms, a substituted hydroxyalkyl group, a sulfoalkyl group having 1-4 carbon atoms, an alkali metal salt thereof, or an ammonium salt; R represents a halogen atom, CR, SR,

R and R each represents a hydrogen atom, an alkyl or hydroxyalkyl group having 1-l2 carbon atoms, a sulfoalkyl group (or an alkali metal salt or ammonium salt thereof), a carboalkyl group (or an alkali metal or ammonium salt thereof), an aralkyl group, an aryl group having 6-18 carbon atoms, a hydroxycarboxy or sulfonic acid derivative of the aryl group, or an alkali metal or ammonium salt of the aryl group, a cyaloalkyl group having 6-10 carbon atoms, or a substituted cycloalkyl group; A represents an alkylene group having 4-5 carbon atoms or an alkylene group having a hetero atom or hetero atomic group; Y represents an alkylene group having 2-10 carbon atoms, a substituted alkylene group, an alkylene group having 6-18 carbon atoms, or a substituted alkylene group; Z represents a divalent hetero atom or atomic group; m is 0 or 1; and M represents an alkali metal or ammonium group.

These fluorescent whitening dyes which may be employed in the present invention are well-known to those skilled in the art and are readily commercially available by the trade names of B1ankophor" (Farbenfabriken Bayer A. 6.), Leucophor" (Geigy Chemical Corp.), Tinopal (Sandoz A. G.), Uvitex (Ciba Ltd.), Kayaphor (Nippon Kayaku K. K.), Potamin White (Dupont), Whitex (Sumitomo Chemical Industries Co. and YL (Honshu Chemical Co.). For example, Blankophor B is a fluorescent whitening agent corre- The water-soluble high molecular weight compound used in this invention may be either a homopolymer of an N-vinyl amide represented by the general formula CH =CHNR,COR or a copolymer of such N- vinylamide and another monomer such as acrylamide, methacrylamide, N-methylacrylamide, N,N- dimethylacrylamide, N,N-diethylacrylamide, acryloyl morpholine, N-methylolacrylamide, N-hydroxyethylacrylamide, acrylic acid, methacrylic acid, methyl acrylate, hydroxethyl acrylate, acrylonitrile, l-vinyl-2- methylimidazole, N-vinylpyridine, 4-vinylpyridine, N- vinylpyrrolidone, N-vinyloxazolidinone, N- vinylcaprolactam, N-vinyl-5-methyl-2-oxazolidinone, vinyl acetate, maleic anhydride, sodium p-vinylbenzene sulfonate, or methyl vinyl ether.

The aforesaid N-vinylamide compound represented by the above general formula may be easily prepared by reacting the corresponding N-alkylacyl compound represented by the general formula R CONHR and acetylene in an autoclave in the presence of an alkali catalyst.

As examples of the N-vinylamide compound, there may be mentioned N-vinyl-N-methylformamide (boiling point 73C at a pressure of 50 mm. Hg), N-vinyl-N- methyl acetamide (boiling point 63C/l7 mm. Hg), N-vinyl-N-methylpropionamide (boiling point 75C/l7 mm. Hg), N-vinyl-N-ethylformamide (boiling point 81C/50 mm. Hg), and the like.

The desired polymer may be obtained by dissolving the above N-vinylamide compound in a solvent such as water, an alcohol, benzene, ligroin or the like and conducting the polymerization in a nitrogen gas stream at a temperature of about 40l00C in the presence of a catalyst such as hydrogen peroxide, potassium persulfate, 2,2'-azobisbutyronitrile, or the like.

In the case of preparing the copolymer of this invention, it is preferable for improving the whitening effect that the proportion of the aforesaid comonomer be less than mole% of the total amount of copolymer.

ln order to obtain the desired whitening effect, higher molecular weight polymers are desirable foruse in the present invention, and the molecular weight is preferably in the range of about 50,000500,000 (intrinsic viscosity 0.2-l .5 in an aqueous solution at 30C). Particularly useful are polymers having a molecular weight of about 100,000-400,000 (intrinsic viscosity 05-12 in an aqueous solution at 30C). However, polymers pos-.

sessing molecular weights above and below these ranges may be employed.

When using the aforesaid conventional N- vinylpyrrolidone polymer, if the molecular weight thereof is higher than 100,000, and particularly if it approaches about 360,000, the miscibility of the polymer with gelatin is degraded, whereby the surface of the photographic printing paper tends to be severely matted. On the other hand, the aforesaid N-vinylamide polymer of this invention having a molecular weight of higher than 100,000 shows a good miscibility with gela tin and moreover even if the molecular weight thereof is over 300,000, very little lack of miscibility occurs, provided the amount of the polymer employed is not excessive, that is, not more than about 60 percent by weight.

There exists no particular limitation on the amount of the N-vinylamide polymer or copolymer of the present invention provided sufficient polymer is present to obtain the desired whitening effect. In general, at least 5 percent by weight of the polymer based upon the total weight of polymer and gelatin binder is desirable to obtain significant whitening effect. However, since the use of an excess amount of the polymer does not substantially increase the whitening effect over a value achieved by about 40% by weight, and in fact reduces miscibility with gelatin and causes a degradation of the quality of the image and is in addition uneconomical, the preferred amount of polymer employed is about 5-40 percent by weight. Most preferably, the amount employed is about 15-25 percent by weight.

As mentioned above, the photographic layers of the photographic printing element of this invention include any of a silver halide emulsion layer, a baryta layer, an undercoating, a protective layer applied to a support such as paper, synthetic resin film, a glass plate or a metal plate and an image receiving layer for a diffusion transfer printing element applied to the support. The fluorescent whitening dye and the water-soluble high molecular weight compound may be incorporated in any one of the above photographic layers to provide the desired effect. Further, the water-soluble high molecular weight material may be incorporated in a different photographic layer than the layer containing the fluorescent whitening dye.

Also, the invention has been exemplified above in terms of using gelatin as the binder. However, other binders such as synthetic resins may be similarly employed in the present invention.

By the present invention, a photographic printing element providing the same or a superior effect than conventional photographic elements containing an N- vinylpyrrolidone polymer or an N-vinyl-S- methyloxazolidione polymer is provided without resulting in the matting of the surface encountered in the conventional methods.

The invention will be explained more practically based on the following examples.

EXAMPLE I To a gelatino silver halide emulsion containing 50 g of gelatin and 20 g of silver chlorobromide (containing 30 mole% silver bromide) were added 0.5 g of the fluorescent whitening agent Blankophor EU?" (trade name of Farbenfabriken Bayer A. G.) and 10 g of an N-vinyl-N-methylacetamide homopolymer having an intrinsic viscosity of 1.05, 0.58, or 0.32 in an aqueous solution of 300C. Then, after adding to the emulsion formaldehyde as a hardening agent and saponin as a wetting agent, the resulting silver halide emulsion was applied to a photographic baryta paper of g/sq. meter to provide a photographic paper. The photographic paper thus prepared was processed in a developer and a fixing solution having the following compositions respectively;

Developer Metol (p-methylaminophenol sulfate) l.() g Sodium sulfite (anhydrous) 15 g Hydroquinone 4 g Sodium carbonate mono-hydrate 27 g Potassium bromide 1.3 g

Water to make 1 liter Fixing Solution Crystalline sodium thiosulfate 240 g Sodium sulflte (anhydrous) g Glacial acetic acid 13.3 g

Borax 7.5 g

Powdered potassium alum 15 g Water to make 1 liter The sample was washed with running water of 15C for l, 5, or 24 hours.

The photographic paper thus prepared and processed was tested for intensity of fluorescence, the results of which are shown in FIG. 1 of the accompanying drawing. In FIG. 1, there is shown the relation between the water-washing time and the relative intensity of fluorescence, which was a relative value when the whiteness of the surface of the photographic paper itself was assumed to be 25. In the figure, curve (1) stands for the results in the case of using the high molecular weight compound having an intrinsic viscosity of 1.05, curve (2) for the case of using the high molecular weight compound having an intrinsic viscosity of 0.58, and curve (3) for the case of using the high molecular weight compound of an intrinsic viscosity of 0.32. Curve (a) in the figure represents a control run, using a paper prepared as above, but having incorporated therein only the fluorescent whitening dye and not the water-soluble high molecular weight compound.

As will be understood from the results shown in FIG. 1, the intensity of fluorescence of the photographic papers of this invention was remarkably higher than the result of the control sample shown by curve (a) and among the photographic papers of this invention, the sample having the water-soluble high molecular weight material having a higher molecular weight gave higher intensity of fluorescence. Moreover, even though the water-soluble high molecular weight compound having a higher molecular weight was employed, the surface properties of the photographic paper were not injured. Also, very little reduction in whiteness by water washing was observed.

EXAMPLE II To one liter of a baryta coating dispersion having the following composition were added one gram of Blankophor BUP" as the fluorescent whitening dye and 10 g of an N-vinyl-N-methylformamide polymer having an intrinsic viscosity of 1.05 (molecular weight of 400,000):

Barium sulfate 500 g Gelatin 50 g Chromium alum 2 g Formalin (30%) 0.3 ml

Water to make 1 liter The baryta coating composition was applied to a paper in a thickness of 100 g/sq. meter. To the baryta coated paper was applied a gelatino silver halide emulsion containing 50 g of gelatin and g of silver chloride and having added thereto formaldehyde as a hardening agent and saponin as a wetting agent followed by drying.

The photographic paper thus prepared was processed as in Example I and the result was compared with a control paper wherein no N-vinyl-N-methylformamide polymer was incorporated in the baryta layer. The results showed that the whiteness of the surface of the photographic paper of this invention was much better than the control case. Moreover, the whiteness of the photographic paper of this invention was not reduced by water washing.

EXAMPLE III After adding formaldehyde as a hardening agent and saponin as a wetting agent to a gelatino silver halide emulsion containing 20 g of silver chlorobromide (60 mole% silver bromide) per 50 g of gelatin, the resulting silver halide emulsion was applied to a baryta coated paper of I50 g/sq. Before drying the silver halide emulsion layer, an aqueous solution containing 0.7 g of Whitex BF (trade name of Sumitomo Chemical Industries Co.) as a fluorescent whitening dye, 8 g of the N-vinyl-N-methylformamide having an intrinsic viscosity of 0.90, 3 ml of formalin, 6 ml ofa 6 percent methanol solution of saponin, and one liter of water was applied to the silver halide emulsion layer in a setting state and dried. The photographic paper thus prepared was processed and dried as in Example I and the results were compared with a control paper having no N-vinyl-N-methylformamide polymer added. The results showed that the whiteness of the surface of the photographic paper of this invention was higher than the control case. Also, the whiteness of the photographic paper of this invention was not reduced by water washing.

EXAMPLE IV After adding 0.5 g of Kayaphor S (trade name of Nippon Kayaku K. K.) as a fluorescent whitening agent and formaldehyde as a hardening agent and saponin as a wetting agent to a gelatino silver halide emulsion containing 20 g of silver iodobromide (1.5 mole% silver iodide) to 50 g of gelatin, the resulting emulsion was applied to a baryta coated paper of I50 g/sq. meter. To the silver halide emulsion layer in a setting state before drying was applied an aqueous solution containing 20 g of gelatin, 8 g of the N-vinyl-N-methylpropi0neamide polymer having an intrinsic viscosity of 0.98, 3 ml of an aqueous 30 percent solution of formalin, 6 ml of a 6 percent methanol solution of saponin, and one liter of water followed by drying to provide a protective layer.

The photographic paper thus prepared was processed and dried as in Example I and the results were compared with a control having no added N-vinyl-N- methylpropioneamide polymer in the protective layer. The results showed that the whiteness of the surface of the photographic paper of the present invention was much better than in the control. Moreover, the whiteness was not reduced by water washing after process- EXAMPLE V To the baryta coating composition as shown in Example II was added 12 g of an N-vinyl-N- methylformamide polymer having an intrinsic viscosity of 0.85 and the resulting composition was applied to a paper of g/sq. meter followed by drying. To the baryta layer was applied a gelatino silver halide emulsion containing 20 g of silver chlorobromide (30 mole% silver bromide) to 50 g of gelatin and having added thereto formaldehyde as a hardening agent and saponin as a wetting agent. Further, to the silver halide emulsion layer in a setting state before drying was applied an aqueous solution containing 20 g of gelatin, 1

g of the benzidine fluorescent whitening dye of the formula EXAMPLE Vl After adding to one liter of the baryta coating composition as shown in Example ll one gram of the imidazolone fluorescent whitening dye represented by the formula NE /NH as the fluorescent whitening agent and the resulting composition was applied to a paper of 100 g/sq. meter followed by dry. Thereafter, a gelatino silver halide emulsion containing 20 g of silver iodobromide (1.5 mole% silver iodide) to 50 g of gelatin having added thereto 12 g of a copolymer having a mole ratio of N- vinyl-N-methylacetamide to acrylamide of 9:l and an intrinsic viscosity of 0.85 formaldehyde as a hardening agent, and saponin as a wetting agent was applied to the baryta layer followed by drying.

The photographic paper thus prepared was processed and dried as in Example I and the results were compared with a control wherein the aforesaid copolymer was not incorporated in the emulsion layer. The results showed that the whiteness of the surface of the photographic paper of this invention was much better than the control case and was not reduced by water washing after processing.

SOQNB EXAMPLE VII To one liter of an aqueous percent gelatin solution containing colloidal nickel sulflte nuclei were added 0.5 g of Tinopal GS" (trade name of Sandoz A. G.) as a fluorescent whitening dye and 12 g of a copolymer having a mole ratio of N-vinyl-N-methylformamide to methacrylamide of 9:1 and an intrinsic viscosity of 0.75 and the resulting solution was applied to a paper of 85 g/sq. meter. On the layer thus formed was applied a stripping layer mainly consisting of sodium alginate to provide a diffusion transfer image receiving element.

The image receiving element thus prepared was closely placed on a light-sensitive layer having a silver halide emulsion layer which had been exposed. The assembly was passed through a diffusion transferring device and a developer and the image receiving elementwas stripped from the light-sensitive element after 30 seconds. The results were compared with a control wherein the aforesaid copolymer was not employed. The results showed that the whiteness of the white background portions of the positive image was better than the control.

EXAMPLE Vlll To a gelatino silver halide emulsion containing 20 g of silver chlorobromide (30 mole% silver bromide) to 50 g of gelatin was added 10 g of an N-vinyl-N- methylacetamide polymer having an intrinsic viscosity of 1.05 and the resulting silver halide emulsion was, after the addition of formaldehyde as a hardening agent and saponin as a wetting agent, applied to a baryta coated paper of g/sq. meter. The photographic layer was developed in the developer of Example I, but having added thereto 0.7 g/liter of Blankophor BUP and then fixed, washed with water and dried as in Example l. The results were compared with a control where no N-vinyl-methylacetamide polymer was added to the silver halide emulsion layer. The whiteness of the surface of the photographic paper of this invention was better than the control and was not reduced by water washing after processing.

What is claimed is:

1.. A method of developing a photographic element which comprises developing a photographic element having photographic layers in a developer containing a water-soluble fluorescent whitening agent, at least one of said photographic layers containing a water-soluble member selected from the group consisting of a polymer and a copolymer of a compound represented by the formula CH2=CH wherein Rfrpresents a methyl group or an ethyl group and R represents a hydrogen atom, a methyl group, or an ethyl group.

2. The method of claim 1 where said water-soluble flourescent whitening dye is selected from the group consisting of a diaminostilbene fluorescent dye, a ben-' zidine fluorescent dye, a triazole fluorescent dye, an imidazole fluorescent dye and imidazolone fluorescent dye.

3. The method of claim 1 wherein said compound is selected from the group consisting of N-vinyl-N- methylformamide, N-vinyl-N'methylacetamide, N- vinyl-N-methylpropioneamide, and N-vinyl-N- ethylformamide.

4. The method of claim 1 wherein said photographic layer is selected from the group consisting of a baryta layer, an undercoating layer, a light-sensitive emulsion layer and a protective layer.

5. The method of claim 1 wherein said photographic layer is a diffusion transfer image receiving layer.

6. The method of claim 1 wherein said member is a homopolymer.

7. The method of claim 1 wherein said member is a copolymer of said compound and another vinyl comonomer.

8. The method of claim 7 wherein said vinyl comonomer is selected from the group consisting of acrylam- 9. The method of claim 1 wherein the proportion of said vinyl comonomer is less than 20 mole percent of the total amount of copolymer.

10. The method of claim 1 wherein said polymer has a molecular weight of from about 50,000 to about 500,000.

11. The method of claim 1 wherein said polymer is employed in an amount of at least 5 percent by weight based upon the total weight of polymer and a binder. 

2. The method of claim 1 where said water-soluble flourescent whitening dye is selected from the group consisting of a diaminostilbene fluorescent dye, a benzidine fluorescent dye, a triazole fluorescent dye, an imidazole fluorescent dye and imidazolone fluorescent dye.
 3. The method of claim 1 wherein said compound is selected from the group consisting of N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, N-vinyl-N-methylpropioneamide, and N-vinyl-N-ethylformamide.
 4. The method of claim 1 wherein said photographic layer is selected from the group consisting of a baryta layer, an undercoating layer, a light-sensitive emulsion layer and a protective layer.
 5. The method of claim 1 wherein said photographic layer is a diffusion transfer image receiving layer.
 6. The method of claim 1 wherein said member is a homopolymer.
 7. The method of claim 1 wherein said member is a copolymer of said compound and another vinyl comonomer.
 8. The method of claim 7 wherein said vinyl comonomer is selected from the group consisting of acrylamide, methacrylamide, N-methylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, acrYloyl morpholine, N-methylolacrylamide, N-hydroxyethylacrylamide, acrylic acid, methacrylic acid, methyl acrylate, hydroxethyl acrylate, acrylonitrile, 1-vinyl-2-methylimidazole, N-vinylpyridine, 4-vinylpyridine, N-vinylpyrrolidone, N-vinyloxazolidinone, N-vinylcaprolactam, N-vinyl-5-methyl-2-oxazolidinone, vinyl acetate, maleic anhydride, sodium p-vinylbenzene sulfonate and methyl vinyl ether.
 9. The method of claim 1 wherein the proportion of said vinyl comonomer is less than 20 mole percent of the total amount of copolymer.
 10. The method of claim 1 wherein said polymer has a molecular weight of from about 50,000 to about 500,000.
 11. The method of claim 1 wherein said polymer is employed in an amount of at least 5 percent by weight based upon the total weight of polymer and a binder. 